[v2,19/19] crypto: ecrdsa - Fix signature size calculation

Commit Message

Lukas Wunner Sept. 10, 2024, 2:30 p.m. UTC

software_key_query() returns the curve size as maximum signature size
for ecrdsa.  However it should return twice as much.

It's only the maximum signature size that seems to be off.  The maximum
digest size is likewise set to the curve size, but that's correct as it
matches the checks in ecrdsa_set_pub_key() and ecrdsa_verify().

Signed-off-by: Lukas Wunner <[e-mail]>
---
 crypto/ecrdsa.c | 8 ++++++++
 1 file changed, 8 insertions(+)

Patch

diff --git a/crypto/ecrdsa.c b/crypto/ecrdsa.c
index f981b31f4249..b3dd8a3ddeb7 100644
--- a/crypto/ecrdsa.c
+++ b/crypto/ecrdsa.c
@@ -252,6 +252,13 @@  static unsigned int ecrdsa_key_size(struct crypto_sig *tfm)
 	return ctx->pub_key.ndigits * sizeof(u64);
 }
 
+static unsigned int ecrdsa_max_size(struct crypto_sig *tfm)
+{
+	struct ecrdsa_ctx *ctx = crypto_sig_ctx(tfm);
+
+	return 2 * ctx->pub_key.ndigits * sizeof(u64);
+}
+
 static void ecrdsa_exit_tfm(struct crypto_sig *tfm)
 {
 }
@@ -260,6 +267,7 @@  static struct sig_alg ecrdsa_alg = {
 	.verify		= ecrdsa_verify,
 	.set_pub_key	= ecrdsa_set_pub_key,
 	.key_size	= ecrdsa_key_size,
+	.max_size	= ecrdsa_max_size,
 	.exit		= ecrdsa_exit_tfm,
 	.base = {
 		.cra_name	 = "ecrdsa",